Process for dewatering an aqueous solution containing solids using water-absorbent substances

Abstract

A process for dewatering an aqueous fluid containing solids using water-absorbent substances is disclosed. A water-absorbent substance and a body to which the solids will adhere are added to the solids-containing aqueous fluid. The water-absorbent substance absorbs water and the solids coat the solids-adhering body. The water-laden substance may then be separated from the solid-adhering body that is coated with solids, thereby separating the water and the solids.

What we claim is: 
     
       1. A process for separating solids and water from an aqueous fluid containing said solids comprising: mixing the aqueous fluid with a water-absorbing substance;   allowing the water-absorbing substance to absorb water, creating a water-laden substance;   contacting the aqueous fluid with a solids-adhering body;   allowing the solids to adhere to the solids-adhering body; and   separating the water-laden substance and solids-adhering body having solids adhered thereto, thereby separating the solids and water.   
     
     
       2. The process of claim 1 wherein said water-absorbing substance is a polymeric gel. 
     
     
       3. The process of claim 1 wherein the aqueous fluid is a drilling fluid. 
     
     
       4. The process of claim 1 wherein the aqueous fluid is a coal slurry containing clay. 
     
     
       5. The process of claim 1 wherein said solids are cuttings from a subterranean borehole. 
     
     
       6. The process of claim 1 wherein said solids-adhering body is metallic. 
     
     
       7. The process of claim 1 wherein said solids-adhering body comprises a plurality of metallic balls. 
     
     
       8. The process of claim 1 wherein the step of separating the water-laden substance and the solids-adhering body uses a screen. 
     
     
       9. The process of claim 1 further comprising removing the solids that have adhered to the solids-adhering body. 
     
     
       10. The process of claim 1 further comprising dehydrating the solids adhered to the solids-adhering body and then removing the solids from the solids-adhering body. 
     
     
       11. The process of claim 10 wherein the process of dehydrating said solids adhered to the solids-adhering body is performed by applying heat to said solids. 
     
     
       12. The process of claim 11 wherein the heat applied to said solids is from the exhaust of an engine. 
     
     
       13. The process of claim 1 further comprising removing water from the water-laden substance and then reusing the dewatered substance by repeating the first step of adding the substance to the aqueous fluid. 
     
     
       14. The process of claim 1 wherein the water-absorbing substance is a cellulose ether gel. 
     
     
       15. The process of claim 1 wherein the water-absorbing substance is high-purity acrylic acid polymeric gel. 
     
     
       16. A process for treating a water-based, clay-containing drilling fluid being circulated in a well drilled into subterranean formations, which comprises the steps of: (a) directing a portion of said drilling fluid into a mixer;   (b) directing into the mixer metallic balls;   (c) directing into the mixer a water-absorbent gel;   (d) mixing said water-absorbent gel, said metallic balls, and said drilling fluid portion, thereby allowing the water-absorbent gel to become swollen with water and the clay to coat the metallic balls;   (e) directing the water-absorbent gel, metallic balls, and drilling fluid portion to a separator; and   (f) separating the water-swollen gel and the clay-coated balls.   
     
     
       17. The process of claim 16 further comprising the steps of regenerating the water-swollen gel by shrinking the gel to remove water therefrom. 
     
     
       18. The process of claim 16 wherein regenerating the water-swollen gel is performed by warming the water-swollen gel so that it shrinks to a reduced volume and releases at least a portion of the absorbed water. 
     
     
       19. The process of claim 18 further comprises directing the shrunken gel to step (c) of claim 16. 
     
     
       20. The process of claim 16 further comprises removing clay coated to the metallic balls. 
     
     
       21. The process of claim 16 wherein the steps (b) and (c) are performed simultaneously. 
     
     
       22. A process for dewatering a clay-containing, aqueous coal slurry comprising the steps of adding to said slurry a water-absorbent polymeric gel;   adding to said slurry a body to which said clay has an affinity in the presence of said polymeric gel;   allowing said polymeric gel to absorb water from the aqueous coal slurry and the clay and coal to coat said body; and   separating the water-laden polymeric gel and said body.   
     
     
       23. A process for dewatering an aqueous solution containing a first particulate solids, which comprises introducing to the aqueous solution a second particulate solids, said second particulate solids forming a sticky paste in said aqueous solution when said solution is dewatered;   mixing said second particulate solids with the said first particulate solids;   introducing to the aqueous solution a water-absorbing polymeric gel for absorption of water, thereby causing the second particulate solids to be a sticky paste;   introducing to the aqueous solution a body having an affinity for said second particulate solids in sticky paste form;   allowing said water-absorbing polymeric gel to become laden with water and said first particulate solids and said second particulate solids to coat said body; and   separating the water-laden gel and the body having said first and second particulate solids coated thereon, thereby dewatering the aqueous solution.   
     
     
       24. The process of claim 23 wherein the second particulate solids is clay. 
     
     
       25. The process of claim 23 wherein the first particulate solids is coal and the second particulate solids is clay. 
     
     
       26. A process for dewatering an aqueous solution containing a particulate substance comprising the steps of contacting said solution with a water-absorbent polymeric gel, said gel substantially dewatering said solution leaving said particulate substance as a sticky paste;   contacting said gel and said particulate substance with a body to which said sticky particulate substance will adhere, thereby coating said body with said particulate substance;   directing said gel containing water and said body coated with said particulate substance to a separator; and   separating said gel containing water and said body coated with said particulate substance.